1. Field of the Invention
The present invention relates in general to the field of kitchen appliances and more particularly to an improved range hood. Specifically, a preferred embodiment of the present invention relates to a range hood having a blower located over a heating element, wherein the blower removes cooking effluents and aids in the recirculation of air toward the cook top to an air curtain around the cook top to trap the effluent.
2. Discussion of the Related Art
The below-referenced U.S. patents disclose embodiments that were at least in-part satisfactory for the purposes for which they were intended. The disclosures of all the below-referenced prior United States patents in their entireties are hereby expressly incorporated by reference into the present application for purposes including, but not limited to, indicating the background of the present invention and illustrating the state of the art.    U.S. Pat. No. 6,551,185 entitled “Air Intake And Blowing Device”, pertains to a device with a turbo fan capable of blowing air in a spiral vortex airflow and an intake port for removal.    U.S. Pat. No. 4,475,534 entitled “Ventilating system for kitchen” describes a ventilating system that blows air downward into the front of the hood and also provides a stream in the back at a lower level. An upward directed airflow moves air back into the ventilating system filter area.    U.S. Pat. No. 6,173,710 entitled “Ventilation Systems” relates to a front and two sides for airflow coverage. This system relies on having a wall or physical barriers to provide coverage for the fourth side for air removal.    U.S. Pat. No. 6,620,038 entitled “Suction Exhaust Device” describes a circumference design that also uses fresh air supply for mixing.    U.S. Pat. No. 6,551,185 describes a spiral swirling method for the air curtain and suction action.    U.S. Pat. No. 6,621,058 entitled “Wall-mounted microwave oven with air curtain guide” discloses a front only air curtain.    U.S. Pat. No. 6,058,929 entitled “Adjustable exhaust hood with air curtain” describes a system having two blowers—one for downward flow of air in the front and a second exhaust blower in the back to provide a partial air curtain only to which the sides and back are free to flow out.
Range hoods are of two general types, updraft and downdraft, and within these general categories are ducted and ductless, wall or island hoods. The updrafted, ducted types gather air from above the cooking surface, pass it through a filter where particulates are collected. The air is then channeled into a ducted path and is exhausted to the outdoors. A grease filter is used for removal of some of the grease and particulates. Heat, steam and odors are exhausted to the outdoors in this similar manner.
Present range hoods use a single blower/motor assembly centered in the middle of a range hood for exhausting. Range hoods are centered in the middle of the unit, in order for the hood to draw or create a negative pressure zone for capturing contaminated air. The exhaust blower is sized to draw in the air that is rising and escaping from the work area into the filter. As the size of the range hood gets bigger, the size of the blower must also increase. The blower has to be large in; size, power, speed, and CFM (Cubic Feet per Minute) air movement and thus creates an increase in noise levels. To reduce the noise level, reduction controls have been used. The reduction in output also reduces the ability of the system to effectively draw air into the hood and exhaust. The resulting movement of air outside the hood results in smells, odors, steam, moisture, heat, etc. entering the work area. With the burners located on the outer edges of the cook top range, and the range hood blower/motor located at the center, it is easy to see why the loss of containment can occur.
The controls used presently only provide limited set points in reducing the speed of the motor. They do not provide an unlimited range for setting the proper speed. Moreover, “over-exhausting” may unknowingly reduce home temperatures. It has also blown out flames in appliances and has caused air quality problems.
On the other hand, the ductless types, gather air from the above surface of a range/cooking surface, and pass moisture, effluents, airflow, and temperatures through a filter that collects particulates and greases. This filter is different than the filter used in ducted systems. These filters have a layer of activated carbon charcoal that is either a coating or granules. Because of this activated carbon charcoal layer in the filter, the odor is removed or neutralized as air passes through this layer. The air still carrying heat, steam and some oil/grease, however, is then recycled back into the room by discharging the air through vents in a hood. This makes the user have to move away from the vent opening as it is not a pleasant environment.
Range hoods for the most part are designed so that the front to back dimensions are shorter than the front to back dimensions of a cook top/range. Accordingly, large portions of the front burners are out in front of the top edge of a range hood. As much as 50 percent of the front burners on a range or cooking surface may not be covered by a standard range hood. The reason for this is to permit the user to look into and work on the cooking surface without hitting the range hood. This off-set means that during cooking, steam, smoke, odors, and particulates from the front burner(s) have the ability to pass up in front of the range hood and escape into the room. All blower's motors are centrally located to provide even draw for exhausting, but the flow within this design can be disrupted by any obstruction that enters the hood area including a user's arm. Now add to this a fry pan with low sides and the effective draw zone is at a greater distance from the source and loss of containment occurs. Also the noise level is very high with high speed fans and to some users this level of noise is found to be objectionable. Further, if air streams from outside sources are blowing across a range from an opened door or from a fan in the room, most range hoods cannot provide proper removal of the contaminated air. Major manufactures have attempted to address the above issues of moisture, effluents, airflow, and temperature by blasting a stream of air in a downward flow at the front of the cook top. This is accomplished by blowing air down from the front bottom edge of the hood to create an air pattern that restricts effluents. However, this downward air movement in the front does not accomplish the desired results because air moves out of the captured zone from the sides. Air cannot only move outside the zone from the sides but also out or on to the back wall. Other designs have created a downward flow of air on three sides, but where the back wall collects the grease, moisture, effluents, heat, and temperatures, or it is not contained when an island hood is used. One other method used is to swirl air around in a circle. The problem with this method is that as the air is moving around in a circle if a wall or an item is in the way, stoppage of movement occurs. This stoppage results in a large area of loss entrapment for the contaminated air. This loss then results in the contaminated air being able to escape from a large area and into the room.
Present design range hoods locate the controls on the front or on the under side of the range hood. These controls range from the simplest mechanical switch to a basic electronic control. The mechanical type switches are the rocker, slide, or rotary design. These designs have been around for a long time and are unattractive for high-end units. Such controls are also hard to clean and operate. These switches and controls become coated with grime and functions are reduced. Also, there have been a number of fires as a result of a build up of grease/oils.
The lighting used by most present units is of fixed types, which are directed down. Here, the lights are often not shining in the right location when in use or if one is looking down into the cook top of the range, the user blocks the hood lights. This blocking reduces the light shining on the cook top and in some cases the light is reflected back at the user. When the light fixtures become filled or coated with grease, oils, etc., the lights need to be serviced. To service the lights, some range hood manufacturers have only an incandescent bulb inside that is unscrewed and replaced, others use a single bulb with a plastic shield to protect it. Still other manufacturers use halogen lamps and bulbs to shine light down on the range. The use of halogen type lamps and bulbs pose other problems for cleaning. First, cleaning and replacing is difficult. The lamp types have a glass frame protecting the element and they some times have a metal trim. One must remove the trim to clean or replace the bulb. The other types have a glass lens and bulb inside. If faulty contact is made, the life of the bulb is reduced. The other issue with these types of designs is the ability of the user to do the cleaning and replacement from the underside of the range. Bending over and trying to look under the range hood and clean is not easy, and therefore it is not regularly accomplished. Another issue with using halogen lamps is the cost, which is 3 to 4 times more than an incandescent bulb. A large number of manufacturers only provide a limited number of light levels for the user. These limited light levels are either too bright or too dark. This provides glare or dark spots on the range. The end results of the present lighting methods are generally limited.
There are two families of filter designs. The first designs are the baffle types, which are of a V-shape. This V is both inverted and upright with a gap in between the V for air to move in and around before it goes into the plenum. This design does provide some removal of greases and oils, but a large amount of contaminated air still goes out the duct. This style is used in restaurants and high-end range hoods. The other type is the metal mesh type. Some of these are made of just metal mesh and others also have an activated carbon coating in them. One problem is that most do not tell the user when loss of air removal has occurred. To address this issue on high-end range hoods, manufacturers have added a count down timer for when they believe replacement is needed or cleaning should occur. The filters are timed out ranging from 28 to 30 hours of run time for the range hood for replacement or cleaning. However, this does not address the issue of loss of performance. For example, if the user cooks with a lot of greasy foods, the filters may be plugged sooner than the count-down timing for cleaning would state. On the other hand, if the user does not cook with greases or oils, the alarming would signal change before the filters would need to be cleaned or replaced. Thus, timing on the removal of filters for cleaning or replacement still remains an issue.
The location of heat lamps also poses an issue. That is because they are fitted after the range hood is designed. IR lamps/bulbs for heating or keeping items warm have a very large diameter. The diameter of such a lamp/bulb ranges from 4.5 inches to 7 inches. In taking up such a large area, which reduces the filter area and effective area of containment is reduced. It also reduces the ability to draw contaminated air in.
Finally, in current range hoods, the air flows coming off each of the burners of a range or cook top may be of such strength that they carry cooking moistures, effluents, air, greases, particulates, and heat/temperatures up and around the front, side edges, on to the back wall, or pass by the back if it is an island, and not into the range hood which was intended to collect them.
Therefore, there is a need for a state of the art range hood in which accurate control and removal of moisture, effluent, grease, airflow, particulates and heat/temperature from cooking is Further, there is a need for control(s) to be less susceptible to the environment, and a need for the user to be able to view/see the operation(s), set point(s) functions, speed, and view the contents on the range. There is a need for a remote control, a need to accurately apply and control heat output, as it is returned to the room, and a need for a new design such that it can be used in a variety of places.